rtimer-arch.h

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/*
 * Copyright (c) 2012, Texas Instruments Incorporated - http://www.ti.com/
 * All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
 * are met:
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 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
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 *    from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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/**
 * \addtogroup cc2538
 * @{
 *
 * \defgroup cc2538-rtimer cc2538 rtimer
 *
 * Implementation of the rtimer module for the cc2538
 *
 * The rtimer runs on the Sleep Timer. This is a design choice, as many parts
 * of Contiki like rtimers with a value of RTIMER_ARCH_SECOND being a power of
 * two. The ST runs on the 32kHz clock, which can provide us with an excellent
 * value of 32768 for RTIMER_ARCH_SECOND.
 *
 * Additionally, since the ST keeps running in PM2, we can do things like drop
 * to PM2 and schedule a wake-up time through the rtimer API.
 *
 * \note If the 32kHz clock is running on the 32kHz RC OSC, the rtimer is
 * not 100% accurate (the RC OSC does not run at exactly 32.768 kHz). For
 * applications requiring higher accuracy, the 32kHz clock should be changed to
 * use the XOSC as its source. To see which low-frequency OSC the 32kHz clock
 * is running on, see cpu/cc2538/clock.c.
 *
 * \sa cpu/cc2538/clock.c
 * @{
 */
/**
 * \file
 * Header file for the cc2538 rtimer driver
 */
#ifndef RTIMER_ARCH_H_
#define RTIMER_ARCH_H_

#include "contiki.h"
#include "dev/gptimer.h"

#define RTIMER_ARCH_SECOND 32768

/** \sa RTIMER_NOW() */
rtimer_clock_t rtimer_arch_now(void);

/**
 * \brief Get the time of the next scheduled rtimer trigger
 * \return The time next rtimer ISR is scheduled for
 */
rtimer_clock_t rtimer_arch_next_trigger(void);

#endif /* RTIMER_ARCH_H_ */

/**
 * @}
 * @}
 */